The Wada test might predict postoperative fine finger motor deficit after hemispherotomy

Super-selective Wada test for pre-surgical leg motor function assessment: A case report

INTRODUCTION

Wada test is well-known to assess lateralization of memory and language functions; however, super-selective Wada (ss-Wada) to evaluate motor leg function is rare. We present a ss-Wada test within the anterior cerebral artery (ACA) to assess the motor function of the leg.

METHODS

Retrospective chart review.

RESULTS

Comprehensive phase-I/II surgical evaluation revealed an ictal focus around the left post-central gyrus with immediate involvement around the left para-central regions. To avoid potential right leg motor dysfunction with the surgery, the patient underwent a ss-Wada procedure. Angiography revealed bilateral ACAs were supplied by the left A1 segment. Super-selective microcatheter injection of amobarbital into the left ACA was performed to avoid cross-filling the contralateral ACA. The ss-Wada test confirmed no right leg motor impairment. Afterward, a craniotomy with direct cortical stimulation confirmed that the left-sided ictal/peri-ictal zone had no clear leg motor function. The patient underwent disconnection of that region and remained seizure-free at 10-month post-op follow-up without any motor or sensory deficits in the right limbs.

CONCLUSION

This case demonstrates the proof of concept for ss-Wada in assessing lower extremity motor function. The ss-Wada procedure accurately predicted no motor deficits in the right leg, consistent with preserved motor function post-surgery.

Finger movement functions remain in the ipsilesional hemisphere and compensation by the contralesional hemisphere might not be expected after hemispherotomy -pre- and post-hemispherotomy evaluations in 8 cases

BACKGROUND

We hypothesized that fine finger motor functions are controlled by the ipsilesional hemisphere, and that gross motor functions are compensated for by the contralesional hemisphere after brain injury in humans. The purpose of this study was to compare finger movements before and after hemispherotomy that defunctionated the ipsilesional hemisphere for patients with hemispherical lesions.

METHODS

We statistically compared Brunnstrom stage of the fingers, arm (upper extremity), and leg (lower extremity) before and after hemispherotomy. Inclusion criteria for this study were: 1) hemispherotomy for hemispherical epilepsy; 2) a ≥ 6-month history of hemiparesis; 3) post-operative follow-up ≥ 6 months; 4) complete freedom from seizures without aura; and 5) application of our protocol for hemispherotomy.

RESULTS

Among 36 patients who underwent multi-lobe disconnection surgeries, 8 patients (2 girls, 6 boys) met the study criteria. Mean age at surgery was 6.38 years (range, 2-12 years; median, 6 years; standard deviation, 3.5 years). Paresis of the fingers was significantly exacerbated (p = 0.011) compared to pre-operatively, whereas that of the upper limbs (p = 0.07) and lower limbs (p = 0.103) was not.

CONCLUSION

Finger movement functions tend to remain in the ipsilesional hemisphere after brain injury, whereas gross motor movement functions such as those of the arms and legs are compensated for by the contralesional hemisphere in humans.

Assessing structural integrity of the pyramidal tracts with diffusion spectrum imaging to predict postoperative motor function in pediatric epilepsy patients with hemispherectomy

Background

Hemispherectomy is an effective treatment option for patients with drug-resistant epilepsy caused by hemispheric lesions. However, patients often have deterioration of their motor functions postoperatively. Diffusion spectrum imaging (DSI) was reliable in presenting the natural shape of the white matter fibers. At the same time, the natural sprawl pyramid tract (PT) might be more intuitive for predicting postoperative motor functions. Therefore, we assessed the motor functions by the natural shape revealed by DSI tractography.

Methods

Ten children with drug-resistant epilepsy who were candidates for hemispherectomy performed DSI PTs tractography and transcranial magnetic stimulation (TMS) for motor mapping. The motor function was evaluated with muscle strength and hand grasping capability. Pyramidal tract (PT) structural integrity and TMS mapping results were compared between patients who remained stable and those with deteriorated motor functions. Receiver operating characteristic (ROC) curves with PTs asymmetric ratio were analyzed to evaluate DSI tractography diagnostic value.

Results

All patients underwent DSI acquisition, while four patients successfully performed TMS. One patient had no response to TMS until the maximal machine output was reached. Four patients failed to perform TMS due to lacking cooperation. One patient was contraindicated to TMS. DSI successfully reconstructed the sharp angle fan-shaped PTs within the hemisphere. The accurate fiber distribution with fiber termination and thickness within the lesioned hemisphere was replicated with DSI tractography. No significance was found in patients’ age, sex, seizure frequency, or medication between patients with stable or deteriorated postoperative motor functions. DSI effectively predicted postoperative motor function as stable with damaged PTs, mild deterioration with atrophied PTs, and intact PTs with contralateral innervation confirmed by intracranial stimulation. The area under the curve (AUC) of DSI tractography was 0.84. According to ROC, the cut-off value of PTs asymmetric ratio was 11.5% with 100% sensitivity and 75% specificity. The sensitivity and specificity of TMS were 2/3 and 1/2, respectively.

Conclusions

The anatomic integrity of PTs with DSI tractography could effectively predict postoperative motor function after hemispherectomy. This enables neurosurgeons to inform patients and relatives about postoperative motor functions with direct morphological evidence of PTs to help them with their surgical decisions.

Non-Ruptured Temporal Lobe Dermoid Cyst Concomitant with Focal Cortical Dysplasia Causing Temporal Lobe Epilepsy-A Case Report and Literature Review

Background: Intracranial dermoid cyst is a rare, benign, nonneoplastic tumor-like lesion that could cause seizures, headache, and hydrocephalus. We hypothesized that the temporal lobe dermoid cyst in combination with other factors were causing the epileptic seizure. Methods: We encountered a 17-year-old girl with anti-seizure medication-resistant epilepsy secondary to dermoid cyst located in the temporal region depicted on magnetic resonance imaging (MRI). She showed neither symptoms of meningitis nor rupture of the cyst according to serial MRI. We hypothesized that temporal lobe dermoid cyst in combination with other factors, such as focal cortical dysplasia (FCD), etc., was causing epileptic seizures in this case. She underwent dermoid cyst removal surgery with resection of the tip of the antero-inferior temporal lobe. Results: Histopathological study showed multiple small intramedullary dermoid cysts in the left antero-inferior temporal lobe in addition to MRI lesions and FCD. Conclusion: A patient with medically intractable epilepsy secondary to left temporal lobe dermoid cyst showed multiple intramedullary dermoid cysts and focal cortical dysplasia that might have interacted to create epileptogenicity. To our knowledge, this is the first case report of dermoid cyst concomitant with FCD.

Hemispherotomy can cause post-operative strabismus

BACKGROUND

Hemispherotomy, which involves disconnecting hemispherical fibers, is a treatment option for medically intractable epilepsy. As various neurological disorders can cause strabismus, we hypothesized that hemispherotomy can cause post-operative strabismus in patients with medically intractable epilepsy.

METHODS

Nineteen patients underwent the Hirschberg test before and after hemispherical disconnection surgery. Among the 19 patients, 16 patients (six females and 10 males; mean age, 12.2 years; range, 0.17-43 years) who underwent hemispherotomy were included in this study.

RESULTS

The difference in the angle between the left and right eyes was significantly widened (p = 0.025). Nine (56%) of 16 patients exhibited post-operative chronic strabismus as evaluated with the Hirschberg test. Intermittent strabismus was noticed by family members or caregivers in 10 (63%) of 16 patients. Patients older than 12 years did not show post-operative strabismus as evaluated by the Hirschberg test.

CONCLUSION

Hemispherotomy can cause or worsen post-operative strabismus in pediatric patients.